“These are my children,” says Jeong Kwan as she ushers me through her garden. “I know their characters well, but even after all this time, they surprise me every day.”

Kwan is a Buddhist nun. But she is also rapidly becoming one of the most sought-after chefs on the planet. This precious little patch of land, halfway up a hillside in rural South Korea, is where she quietly cultivates her progeny: aubergines, tomatoes, cucumbers, basil, chilli peppers, wild sesame leaves and plenty more I can’t recognise, or the translator cannot decode.

Shaven-headed Kwan is a tiny, bright-eyed figure with a very real sense of mischief and humour beneath her (predictably) Zen exterior. She’s clearly amused by a situation which has seen her singled out by a number of leading international chefs – led by Eric Ripert of New York’s vaunted Le Bernardin – as a bona fide gastronomic prophet.

The hullabaloo reached such a level that the New York Times dispatched a critic on the 18-hour flight to Seoul, followed by a bumpy four-hour bus ride down to Baekyangsa, the seventh-century temple in the Naejangsan National Park that Kwan calls home. The extravagant pilgrimage was a success. The New York Times hailed the nun’s cuisine as “the most exquisite food in the world”, dubbing her “the philosopher chef”. The name stuck, and TV crews followed.

While hallyu, or the new Korean wave, continues to surge through the restaurant scenes of cities such as New York, London and Los Angeles, and heavyweight chefs like Noma’s René Redzepi travel to the Korean hinterland seeking culinary inspiration, the 59-year-old Kwan has become the movement’s unsuspecting cover star.

None finer: almost all the food Kwan cooks is home-grown or locally sourced. Photograph: Mark Chilvers for the Observer

This is a woman who has never worked in a restaurant, let alone owned one. She’s never had any official culinary training and never published a cookbook. She doesn’t use garlic or onions in her (strictly vegan) recipes – ingredients which some Buddhists believe stimulate the libido. But Kwan has the New York restaurant scene in her thrall, directors climbing the steep, dusty half-mile between the temple and the small hermitage she shares with two other nuns – and an entirely new breed of acolytes queuing up to digest her wisdom. While she finds it the funny side of this, she also sees it as a useful means of propagating her own perspective on food preparation. For her, cooking should never be about greed – the licking of lips and the stuffing of faces. It should be about serving dishes as a means to a higher end: clean bodies and clean minds.

Food is meant to nourish your body and help your mind find enlightenment

“Food is meant to nourish your body and help your mind find enlightenment,” she says. “It’s a way of bringing humans back to nature, of clearing our minds for meditation. This is how we grow.” To illustrate her point, she jabs a tiny finger in my direction. “You’re the soil,” she says. “Food is the seed.”

“Overcome” is a word Kwon uses a lot. Hunger is something to be “overcome”. The changing seasons, and their effect on her vegetable garden, are likewise to be “overcome”. And her food itself, in a way, is about overcoming, too. Overcoming gluttony in all its guises and eating simple dishes to clarify mind, body and spirit.

Broad range: Kwan in the kitchen. Photograph: Mark Chilvers for the Observer

Just as Kwan’s cooking eschews “overly spiced, overly sized” western cooking, so too does her temperament. In her simple grey robes, a gentle smile almost permanently fixed to her face, she is the antithesis of the ranting, narcissistic TV chefs of the modern celebrity era.

As we climb the few hundred metres to her hermitage, she points out thriving nutmeg, enormous mushrooms she’s been cultivating for months and a rare, 500-year-old Taengja tree which still produces oranges she uses in her recipes. There is literally no distance between Kwan and her ingredients: this is less farm to table, more garden to altar. “Flavours still surprise and excite me every day,” she says. “Each moment I am thinking about the cooking, the ingredients, the recipes.”

Flavours still surprise and excite me every day

Kwan’s wooden home is, as you might expect, very basic. Here she cooks for two other nuns and occasionally some of the 50 or so monks based down the hill at the temple. As we talk, she prepares lunch. It’s already late in the day (we rose shortly before 5am for Buddhist meditation and chanting – a compulsory undertaking for temple guests), but Kwan flits energetically about her kitchen, robes fluttering like one of the butterflies in her garden.

Simple as it looks, the resulting food has an instant impact. As the small dishes arrive in swift succession, so too do the surprises: textures melt and harmonise while sharp, delicious flavours appear unannounced as we chew. “She has magic in her hands,” wonders the awestruck translator, her mouth full of pak choi and perilla seeds.

Our wooden bowls fill – marinated aubergine with bean powder; pickled plum with zanthoxylum; pumpkin stuffed with spicy tofu – each delicate and intricate in itself, yet part of an overall symphony of flavours effortlessly conducted by Kwan. Afterwards we feel neither full nor hungry and, if anything, decidedly lighter and more energetic than when we started. Culinary alchemy never tasted so good.

Symphony of flavours: typical ingredients in a Kwan dish. Photograph: Mark Chilvers for the Observer

So where next for the philosopher chef? She’s already been flown to New York twice by Ripert, but for now she’s happy to stay in her hermitage, meditating for a minimum four hours each day. In the long term, she says she’d like to open a temple food restaurant of sorts. In the mid term, publish a recipe book. In the short term, simply tend to her beloved herbs and vegetables. “I have grown and cared for these ingredients, I have poured my energy into them,” she says. “That energy comes out when I prepare them in a meal.”

And perhaps that, above all, is the secret of the Philosopher Chef’s success. Jeong Kwan has mastered the art of cooking with love.

Jonathan Thompson’s road trip across South Korea was supported by Kia Motors UK, which celebrates its 25th anniversary this year. For more information, go to kia-buzz.com